The present invention relates to a position sensor for detecting the position of an operating portion of a device body and more particularly to a position sensor suitable for use in an environment containing moisture and dust such as, a vehicular throttle position sensor.
Generally, a vehicle such as a gasoline-fueled vehicle is provided with a position sensor called a throttle position sensor for setting an optimal amount of fuel to be supplied according to a running speed of the vehicle and thereby allowing the vehicle to run in an optimal fuel consumption.
Heretofore, as an example of a throttle position sensor of this type, there has been known, as described in Japanese Utility Model Laid-Open No. Hei4-8401(1992), a position sensor in which a sensor body comprising a sliding-element receiver and a resistor substrate is mounted in the interior of a receptacle chamber formed in a housing, a cover is applied to an opening of the receptacle chamber, and a clearance between the receptacle chamber and the cover is sealed with a thermosetting resin. In such a known position sensor, a communication hole is formed for communication between the receptacle chamber and a connector portion which is integral with the housing, and at the time of heat-curing the thermoplastic resin for sealing, the air expanded within the receptacle chamber is allowed to escape through the communication hole to the exterior of the connector portion. In this way the rise of pressure in the receptacle chamber at the time of heat-curing the thermosetting resin is suppressed to thereby prevent the formation of pores or the like in the thermosetting resin.
According to the above prior art, since the insertion of an external connector into the connector portion is done after mounting of the position sensor to a device body of a vehicle or the like, the communication hole formed in the interior of the connector is kept dust- and waterproof against the exterior. However, no consideration is given to preventing the entry of dust and water in the interior of the housing.